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Analysis

Descriptive statistics included frequency analysis (percentages) for
nominal variables and means ± standard deviations (SDs) or medians and
interquartile ranges (IQRs) for continuous variables, according to
their distribution. The survival curve after hospital discharge and
median survival time were estimated by the Kaplan-Meier method, and
patients who were still alive at the date of follow-up (15 June 2009)
were censored. The survival of our cohort was compared with the
survival curve for the French population as a whole, established from
mortality data obtained in 42,336 people who had a mean age of 84
years.^[19] The standardized mortality ratio (SMR) method
was used to compare the hospital mortality observed in our cohort with
SAPS II-predicted mortality and to compare the mortality observed in
our cohort at 2 years after discharge with age- and gender-adjusted
mortality of the general population. We used a Cox survival analysis
to identify independent predictors of mortality at the hospital and of
mortality at 2 years after hospital discharge. For the latter,
survival was measured from the first day after discharge, and patients
alive at 2 years were censored. First, univariate analysis was
performed for each potential factor. Factors with a P value of
less than 0.2 in the univariate analysis were then introduced as part
of a backward stepwise Cox proportional hazard model. Hazard ratios
and 95% confidence intervals (CIs) were calculated. In the final
multivariate model, a P value of less than 0.05 was considered
significant. Factors significantly associated with mortality in the
multivariate model were tested for a possible interaction. Statistical
analysis was performed by means of SPSS 15.0 software (SPSS, Inc.,
Chicago, IL, USA).

Results

Patients

Of the 2,411 patients admitted to the ICU during the 6-year study
period, 299 (12.4%) who were at least 80 years old (84 ± 4 years; range
of 80 to 97) were included (Table 1). Among them, 176 (59%) were
mechanically ventilated for a median duration (IQR) of 4 days (2 to 9).
The median duration (IQR) of ICU stay was 5 days (3 to 9). Eleven
patients had one or more ICU readmissions, but none of them had been
discharged from the hospital between ICU stays.
Intensive Care Unit and Hospital Mortality

ICU mortality was 46% (138/299), and mortality throughout the duration
of hospital stay was 55% (166/299). Factors associated with hospital
mortality are detailed in Table 1. After multivariate analysis, the
factors found to be significantly associated with increased hospital
mortality were a higher SAPS II at ICU admission, the existence of a
fatal disease as reflected by the McCabe score, and a cardiac diagnosis
at admission. No significant interaction between factors associated
with hospital mortality was found. The SMR of our cohort was 0.99 (95%
CI 0.84 to 1.18) when compared with SAPS II-predicted mortality.
Mortality at 2 Years after Hospital Discharge

Of the 133 patients (45% of the initial cohort) who were discharged
from the hospital, 49 died over the course of the first year after
discharge and 21 died during the second year (no loss to follow-up).
Thus, 1-year mortality after admission was 72% (215/299) and 2-year
mortality after admission was 79% (236/299). Two-year mortality in
hospital survivors was 53%, whereas in the same age group for the
general French population, it was 18%.^[19] Age- and
gender-adjusted SMR of our cohort was 2.56 (95% CI 2.08 to 3.12) when
compared with the general population. The survival curve after hospital
discharge is shown in Figure 1. The estimated median survival time
after hospital discharge was 710 days (95% CI 499 to 921). We analyzed
which factors, available at ICU admission, could be predictive of
mortality at 2 years after hospital discharge (Table 2). After
multivariate analysis, the factors found to be significantly associated
with increased mortality were a higher SAPS II at ICU admission and
the existence of a fatal disease as reflected by the McCabe score.
Conversely, functional status, as evaluated by the Knaus classification
or the Karnofsky index before ICU admission, was not significantly
associated with mortality at 2 years in hospital survivors. No
significant interaction between factors associated with mortality at 2
years after hospital discharge was found. When multivariate analysis
was conducted in patients who were still alive 30 days (n = 120), 90 days (n = 112), or 180 days (n
= 100) after discharge, SAPS II was also significantly associated
with mortality at 2 years after hospital discharge. However, it was no
longer associated with mortality (P = 0.13) in survivors at 1 year after discharge (n = 88).



.
[ CLOSE WINDOW ]<blockquote> </blockquote> Figure 1.

Kaplan-Meier survival curve of hospital survivors in comparison with that of the general French population. Age in both groups was a mean of 84 years. Mortality data for the latter were obtained from [19].


Long-term Health-related Quality of Life

HRQOL using SF-36 was prospectively evaluated in the 24 patients who
were still alive at the time of evaluation in June 2009 (no loss to
follow-up). Their median age (IQR) at evaluation was 89 years (87 to
92). The median time (IQR) between hospital discharge and SF-36
evaluation was 63 months (56 to 85). Twenty-one patients answered the
questionnaire by themselves, and 3 with the help of a third party.
Scores of physical function were low (Figure 2). Indeed, mean scores ±
SD were 29 ± 12 for physical function, 20 ± 12 for physical role (which
evaluates limitations due to physical function), 31 ± 11 for energy,
and 24 ± 10 for general health (which evaluates the perception of
health). In contrast, scores of bodily pain (56 ± 10), emotional
well-being (56 ± 9), social function (52 ± 15), and emotional role (48 ±
22) (which evaluates activity limitations due to mental health) were
not much affected.

Discussion

This follow-up study
was conducted in a population of severely ill medical patients who
were at 80 years old (84 ± 4 years) and who were admitted to the ICU.
In this population, hospital mortality was 55%, and 47% of hospital
survivors were alive at 2 years. Both hospital and post-discharge
mortality rates were dependent mainly on the severity of acute illness
and on the existence of a pre-existent underlying disease.
Conversely, pre-admission functional scores as evaluated by the Knaus
classification or the Karnofsky index before ICU admission did not
affect mortality at the hospital or over the 2-year period following
discharge.
The reported hospital mortality rate of 55% in our patients is higher
than in several recent studies of much older patients, in which
hospital mortality rates ranging from 12% to 41% were reported.^[5,20–26] However, some of these studies were performed in patients who were just 65 years old or older,^[20–25] in populations with lower severity scores or lower rates of mechanical ventilation,^[5,20,25,26] in surgical or mixed populations of medical and surgical patients,^[20–22] or in patients with a previously healthy status.^[23] Conversely, De Rooij and colleagues^[11]
reported a 56% mortality rate in 146 medical patients who were at
least 80 years old, with a rate of mechanical ventilation and severity
scores that were similar to those described in the present study. Upon
comparison, medical patients had a worse prognosis than surgical
patients. Subsequently, these authors reported a 75% mortality rate at 2
years after admission,^[11] which is close to our results.
The long-term follow-up indicates that mortality of our patients in
the 2 years after discharge was two- to three-fold the mortality of the
general French population of the same age. However, after this time,
the evolution of survival over time was comparable to that of the
general population. Therefore, we analyzed which factors could be
associated with prognosis during this period of over-mortality. We
observed that severity score at the time of admission independently
affected mortality in this 2-year period following discharge. This is
an interesting result since it shows that the severity of an acute
illness will influence outcome after ICU and hospital discharge. The
results of additional analysis in survivors at different time points
after discharge suggest that the severity at admission negatively
influences prognosis mainly during the first months after discharge.
Conversely, we found that Knaus and Karnofsky scores of functional
status before admission did not influence mortality in the 2 years
after discharge. In a previous report, Bo and colleagues^[25]
showed that dependence for regular daily activities was independently
associated with hospital mortality in medical ICU patients who were
at least 65 years old. In that study, severity scores and hospital
mortality (14.7%) were much lower than in our patients, far fewer
patients required mechanical ventilation, and two thirds were
independent for regular daily activities before ICU admission.
Similarly, Sacanella and colleagues^[23] found that full
autonomy before ICU admission was independently associated with a lower
mortality rate after discharge in patients at least 65 years old. In
contrast, in older patients such as those of the present study, only
15% of patients had no functional limitation. Therefore, the ability to
identify functional status as a prognostic factor in such a
homogeneous population is limited. However, since functional limitation
is frequent in much older patients, our results suggest that care
should be taken when using it to make admission decisions and in the
determination of treatment intensity in this category of patients.
Nevertheless, our results contrast with those of Boumendil and
colleagues,^[24] who found a severe or total functional
limitation to be independently associated with mortality after
discharge in 233 medical patients who were at least 80 years old. In
this latter study, included patients had lower severity scores and a
much lower ICU mortality rate (16.3%) in comparison with those of the
present study. Discrepancies between previous studies and the present
report on the influence of functional status on long-term mortality
could be partly explained by a higher rate of patients with severe
limitation in our study and by the selection in other studies of
patients in good condition, who are able to recover well after ICU
discharge.
We prospectively evaluated HRQOL in the 24 long-term survivors. The
scores for physical function were poor, but scores for bodily pain,
emotional well-being, and social function were not much different from
those of other populations of octogenarians.^[27] These latter results could be positively interpreted. Indeed, Nilsson and colleagues^[28]
interviewed healthy individuals who were 77 to 87 years old on the
quality of their lives and showed that the importance of material values
declined but that the importance of social relations and spending
time by oneself increased with increasing age, suggesting that
'quality of life' has a different meaning for older individuals than
it does for younger ones. In ICU patients, Tabah and colleagues^[21]
recently found that quality of life was similar between (a) patients
who were at least 80 years old and who survived 1 year after discharge
and (b) reference populations of the same age and that quality of
life was not modified after the ICU stay. In contrast, in a previous
study in a similar population, the same group showed a decrease in
quality of life 1 year after ICU stay.^[2] In the present
study, we evaluated HRQOL of long-term survivors a median of 5 years
after discharge. Recently, Cuthbertson and colleagues^[29]
showed that the physical component of quality of life worsened faster
in the 5 years following ICU stay than in the general population.
Additionally, Unroe and colleagues^[30] showed that age was
associated with an increased risk of high functional dependency
following prolonged mechanical ventilation. Therefore, our results of
high long-term mortality in the most severely ill medical patients in
the age group discussed here and of severe functional disability in
long-term survivors could help physicians to explicitly discuss
treatment decisions with surrogates on the basis of the future
functional dependence that patients will likely experience.
This study has several limitations. First, this is a single-center
study, and owing to variations in admission policies, caution must be
taken in translating these results to other ICUs. Second, the analysis
of factors associated with survival after ICU discharge did not include
parameters occurring after ICU discharge, such as repeated ICU
admissions or institutionalization. However, the goal of this study was
to help clinician decision-making on the basis of data available
during ICU stay. Third, only very few patients were long-term
survivors, and further studies are required to evaluate HRQOL in much
older patients in the years following ICU discharge. Finally, although
we found that functional status prior to ICU admission was not
associated with mortality either at the hospital or after discharge,
it was determined after admission by physicians using information
obtained from the patient or from proxies. Moreover, we cannot rule
out that other scores of functional status may be more accurate in
predicting long-term outcome in much older patients.


Conclusions

Our study provides
information about short- and long-term outcome for a large group of
much older patients in the medical ICU. We showed that the severity of
acute disease at admission influences mortality at the hospital and
also after discharge. Conversely, functional status prior to admission
did not influence short- and long-term prognosis in this category of
frequently dependent patients. Although up to 50% of patients
discharged from the hospital were still alive at 2 years, mortality in
the 2 years following discharge was three times the mortality observed
in the same age group in the general population. Finally, physical
function of long-term hospital survivors was greatly altered, but other
components of HRQOL were not much affected when compared with the
general population. These results could help the clinician make
decisions with regard to the most severely ill patients in this age
group.

http://www.medscape.com/viewarticle/738247_5